mm, vmscan: remove duplicate logic clearing node congestion and dirty state

Reclaim may stall if there is too much dirty or congested data on a
node.  This was previously based on zone flags and the logic for
clearing the flags is in two places.  As congestion/dirty tracking is
now tracked on a per-node basis, we can remove some duplicate logic.

Link: http://lkml.kernel.org/r/1467970510-21195-12-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 01fe4708e4045a55d8894b76116f625de4ec4f5e..8b39b903bd14dde14b25849d26cd560d7e7a943b 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3008,7 +3008,17 @@ static bool zone_balanced(struct zone *zone, int order, int classzone_idx)
 {
        unsigned long mark = high_wmark_pages(zone);
 
-       return zone_watermark_ok_safe(zone, order, mark, classzone_idx);
+       if (!zone_watermark_ok_safe(zone, order, mark, classzone_idx))
+               return false;
+
+       /*
+        * If any eligible zone is balanced then the node is not considered
+        * to be congested or dirty
+        */
+       clear_bit(PGDAT_CONGESTED, &zone->zone_pgdat->flags);
+       clear_bit(PGDAT_DIRTY, &zone->zone_pgdat->flags);
+
+       return true;
 }
 
 /*
@@ -3154,13 +3164,6 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
                        if (!zone_balanced(zone, order, 0)) {
                                classzone_idx = i;
                                break;
-                       } else {
-                               /*
-                                * If any eligible zone is balanced then the
-                                * node is not considered congested or dirty.
-                                */
-                               clear_bit(PGDAT_CONGESTED, &zone->zone_pgdat->flags);
-                               clear_bit(PGDAT_DIRTY, &zone->zone_pgdat->flags);
                        }
                }
 
@@ -3219,11 +3222,8 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
                        if (!populated_zone(zone))
                                continue;
 
-                       if (zone_balanced(zone, sc.order, classzone_idx)) {
-                               clear_bit(PGDAT_CONGESTED, &pgdat->flags);
-                               clear_bit(PGDAT_DIRTY, &pgdat->flags);
+                       if (zone_balanced(zone, sc.order, classzone_idx))
                                goto out;
-                       }
                }
 
                /*